Numbers / 637

The Number 637

637 is composite: factorization 7^2 × 13. That gives 637 exactly 6 divisors: 1, 7, 13, 49, 91, 637. 637's proper divisors total just 161, 476 short of 637, the deficient case most of 637's neighbors share too. 637 has a digit sum of 16; for 637, the digital root works out to 7. 637: 7 all divide 637 evenly, out of 2-12. 637 is 1001111101 in binary and 27D in hex; as a Roman numeral it's DCXXXVII.